This week: Some cool examples of predation by a predator, you've probably NEVER heard of! And yet, they are deadly, efficient and can take down prey or food that is MANY times their body size.

I am of course talking about the Nemertea aka the Ribbon worms (or sometimes the proboscis worms)! This is actually a whole PHYLUM of worms, which in spite of their superficial appearance, are actually VERY different from flatworms and have a very significant number of internal features..

There's somewhere in the neighborhood of 1300 species of ribbon worms. Most are flattened and can be VERY elongate with some (e.g., Lineus longissimus) approaching 60 METERS (nearly 200 feet) long! Most occur in the oceans but there are freshwater and terrestrial species as we'll see.

They capture food using an eversible proboscis which, thanks to the internet's fascination with weird, gross stuff, you have undoubtedly seen in a variety of formats. Here's two of the popular ones: the red Thailand species expelling its bizarre, almost fractal proboscis:

This proboscis is one of the primary defining characteristics of this group.

Here's the thing though, the above two video/gifs? Showed these animals in stressed situations outside of their natural environment. And NOT demonstrating their mastery of their predatory proboscis appeasing their ravenous rhyncocoel!

These animals likely represent a HUGE ecological impact which is probably difficult to study owing to their rather cryptic nature.

Here today is a nice little collection of ribbon worms "strutting their stuff" with some GREAT images showing attacking/devouring prey (thanks to YouTube and Flickr!)

Some ribbon worms such as these huge Antarctic ribbon worms (Parborlasia corrugatus) are both scavengers AND predators and have been reported as feeding on nearly ANYTHING: fecal pellets, starfish, dead seal meat, fish, sponges, sea anemones, worms amphipods, penguin meat AND sardine meat with tomato sauce! and on and on....

5. POLYCHAETE WORMS! Polychaete worms of various types appear to be a popular food among ribbon worms.Here's one image by James Zhan showing a large ribbon worm consuming a "paddle worm"

This one is impressive. You can actually watch the proboscis IN ACTION as its used to attack its polychaete prey!

3. INSECTS and land arthropodsMost ribbon worms live in the ocean, but a sparing few have gotten into freshwater and even terrestrial habitats! And yes.. with those same predatory habits!

I'll be honest though, some of these can be pretty difficult to ID even to phylum. these were identified as ribbon worms but I suppose they could easily be flatworms.

2. Snails! Flickr users Marvyn Yeo and "Paul" brings us stunning pictures from Asia and Ecuador showing this ribbon worm attacking this snail! Apparently by working its way into the shell aperature and attacking the animal in its own shell.

1. FISH!! and finally the pièce de ré·sis·tance! To be sure, I'm don't think that these worms actually captured these fish, BUT they are very clearly DEVOURING THEM.

Many ribbon worms have a stylet or thorn which is thought to deliver a toxin against some prey items.. so is it entirely unreasonable to suggest they capture fish, esp. prey much larger than them? Probably not. This one is from the Falkland Islands/Malvinas..

And of course leave it to the folks at Tokyo Sea Life Park to capture this AWESOME video of Parborlasia corrugatus An Antarctic ribbon worm devouring this mackeral in time lapse! (Although Parborlasia is pretty big relative to that fish-its still impressive to watch)

The proboscis is close..but I'm thinking.. polychaete instead (dholes do seem to be segmented worms after all)? But that only suggests that if dholes are derived polychaetes than a giant Cthuloid Ribbon Worm may yet be lurking in the darkness....

This week, in the category of "one of those posts only Echinoblog could write"! Let us explore the vibrant diversity of echinoderm anal structures!! Perfectly SAFE for Work! even though it contains the word "anal" and "anuses" several times! WOO!!

Echinoderms are pentaradial (aka pentameral). That is they show a form of radial symmetry wherein their body always occurs around a top-down axis in five parts (although arms, etc. may vary).

As a consequence, the overall dynamic of their life mode is different from an animal with bilateral symmetry. No face, no "front" or "back". Thus, the way food moves through the body is different depending on where the mouth is located and consequently, where the anus is located!!

Since each living class of echinoderms has a fairly unique shape and body morphology, each group has a bunch of unusual specializations that function to facilitate the expulsion of poop!

To be honest, not every member of each class below has what is shown below. These are unusually prominent examples..but it still begs the question "What is it used for?" How many other animals have so many unusual anal adpations??

5. Crinoids: Anal Chimneys & PyramidsSo, crinoids are suspension feeders. They almost kind of resemble plants. Most living ones are known as "feather stars" and are basically cups with arms for filtering water. But earlier forms of crinoids are known as "stalked crinoids" which have a stalk. I had a gallery of the older Paleozoic ones here a few weeks ago..

Here's a living one from the recent Okeanos Expedition to the Marianas region to give you an idea of what they look like..

So, the mouth in stalked crinoids is inside that cup at the base of where all those arms converge. The anus for these animals is ALSO in the cup. So, there's likely a strategy/adaptation for these animals to push the poop/excreta OUT of the anus, such at it does not end up getting "re-eaten" by the mouth...

According toFossil Crinoids by Hess et al. there were several fossil (Paleozoic) forms which had fairly straightforward strategies for dealing with ensuring that poop was discharged FAR from the mouth..

For example, here is the Mississippian Uperocrinus nashvillae with an explanatory diagram from Fig. 37 of Hess et al's book. Basically that huge pointed structure on top? That's called the anal tube (or sometimes in other animals.. an anal pyramid or even an anal chimney!)

These extended structures serve to project the anus (and the excreted poop) well AWAY from the mouth (the feeding arms would come off right at that wide "ledge" around the center of the specimen..

There was a surprising diversity of these structures. Here's another one called Macrocrinus verneuilianus which is a fossil from the Carboniferous (the Paleozoic). The drawing below is taken from the Wooster Geologist blog and they point out that the elongate anal tube (in the lower left hand corner) aka the anal chimney may have even served an additional function beyond simply transporting poop away from the mouth:

The tube allowed waste products to be whisked away far from the mouth of the crinoid, which was at the base of the arms. Some researchers suggest that the long tube served another function as well: it may have helped stabilize and direct the filter-feeding fan of outstretched arms in a stiff current, something like the tail of an airplane or a panel on a weather vane.

One last weird crinoid is this one: Bicidiocrinus wetherbyiAnother Mississippian (i.e Paleozoic) stalked crinoid.. and this is kinda weird. So, there's the cup and the arms and that cone is the anal cone (=tube, pyramid, chimney, etc.) BUT it also has this weird additional protective "spiniferous canopy" around it!!

That said, they DID publish a WONDERFUL picture by David Fleetham of Astropyga radiata venting poop OUT of the anal sac!!

Basically, this is a transparent or translucent bulb or sac extension from the anus through which feces passes on its way out of the body.

See those little round things that look like corn kernals? Sea urchin poop!

Here's another great pic found on Flickr, taken by Eunice Khoo of what looks like a small Astropyga sp. clearly showing poop THROUGH the transparent walls of its anal sac (aka anal cone)..

Very nice capture.

But why take my word for it?? Go ahead and watch it here in this video of what looks like either Diadema or Echinothrix.. The poop event takes place at about 0:15 into the video.

But its not JUST shallow-water diadematid urchins that have this anal sac. Here's a deep-water Aspidodiadema from the recent Hawaiian Okeanos expedition. I talk a bit about these here

These were videos of these animals from 2000-3000 METERS below the surface. Aspidodiadematid urchins are classified in the same general group as diadematids. and they too seem to have this anal sac or cone...

3. Ophiuroids: Alas..brittle stars got no anus. In fact, food goes in and goes out the SAME hole: the MOUTH. So..bummer.

2. Anal (or Epiproctal) ConeSea Stars/Starfish in a larger group called the Paxillosida (the mud and/or sand stars) have a specialized structure which sits right on the center of the disk called the anal or epiproctal cone.

A brief anatomical note- Although historically called an "anal cone" these starfish don't actually have a complete gut and so, the opening on the disk center is not actually the anus since it doesn't connect with the interestine. Hence the name "epiproctal": EPI is Greek for "upon" and PROCT is Greek for "anus".. hence the cone or structure UPON the anus..

The cone is basically an outpocketing of the body, extending UPWARDS through the sediment

Observations of Ctenodiscus under hypoxic conditions led to the illustration above. Basically, its thought that the cone gets more enlarged as hypoxia and hydrogen sulfide increases. The extension of the cone extends through the surface, with the tip at the surface. For your typical 6.0 cm diameter animal, these animals can have a cone that can attain 3 to 4 cm and extend 2 to 3 cm above the mud. It can leave this extended for over an hour. As the picture suggests, it can move around and push through sediment as the mud shifts, and etc. So, it can move around.

This also serves to make the top surface of the animal thinner, allowing easier gas exchange and opening up a channel to the surface water above the sediment surface!!

So, in truth, the "anal cones" in these mud stars is NOT really an anus. Its where the anus would be located in other species..and so the labelling of this stucture is kind of a misnomer.. as they are not really used for defecation.

Other "mud stars" such as this deep-sea (3000-6000 m) Porcellanaster also have well-developed "anal cones". These starfish sit buried in sediment with these projections sitting up through the sediment.

In contrast this shallower water Astropecten armatus has a much less developed anal or epiproctal cone. This is also related to the fact that it occurs in shallower water and tends to bury itself in somewhat less sediment compared to the above two species..

1. Sea Cucumbers (Holothuroidea): Anal TeethAnd finally, one of the best known of echinoderm anal defenses: the anal teeth in sea cucumbers!

I've reported on these before. There's at least one interpretation that these structures are defensive in nature and work to keep pearlfishes (and likely other commensals or parasites) from inhabiting the cloaca.

Sea cucumbers get kind of a special award for using their cloacal and other "ass end" chambers most efficiently..especially since some species can actually FEED and BREATH as water passes through the anal opening!! Read more about that here.

This week I do a brief recap of spectacular views from the Okeanos Explorer Expedition to the Marianas Islands which began earlier this week. You can find out all about it on their website here.Long story short, they are in the tropical North Pacific near Guam with access to some of the deepest trenches and canyons in the world!

This first leg began on April 20th and continues until about May 11th. They have been surveying many very deep canyons and seamounts which are at best, very poorly known and reach 5000 m depths or so!

Many, MANY amazing things have already been seen during the last seven days or so. Here's a recap of the things I thought were most fantastic. But check out their blog here.

1. STUNNING Gorgonocephalid Basket Star FieldsSo, on May 2nd, the Okeanos Explorer visited Zealandia Bank, in relatively "shallow" depths about 650 to 250 meters. While surveying this area they discovered this AMAZING field of basket stars!! Apparently in the family Gorgonoceaphlidae. You can read one of my earlier accounts on other members of this family live and feed here. But short story: they have elongate arms with hooks that capture prey carried on the water currents.At this amazing site we had...HUNDREDS of these animals as part of a community of filter-feeding aniamls.

Here's what one looks like closer up.

But again, just spread out EVERYWHERE. At one point Diva Amon, the biology science lead indicated they had travelled about 100 m seeing basket stars to no end!

The animals in this area were all taking advantage of the current flow, including these isocrinid stalked crinoids and those little white corals.

At one point they mentioned that the water current above this field was about 1 knot, which means that the "drag" of this current against the bottom created a good habitat for filter feeding animals.This area included other species of invertebrates.. starfish and so forth, which could have been feeding on the filter feeders or perhaps indirectly taking advantage of other benefits from the current flow (food, etc.).

Personally, this one was my FAVORITE thing to have seen. Just amazing.

2. Hydrothermal Vent Chimneys On May 3rd, Okeanos went to a suite of amazing hydrothermal vent chimneys!!! These are places where hot geothermally heated water is vented out through the earth's crust. The dive went down to about 2000 to 4000 m. VERY deep.

This leaches out hot water with toxic minerals into the surrounding water. Surprisingly however, there are a great MANY animals which are able to process these minerals into food!

On this site, it included specialized limpets and other snails, as well as bythograeid crabs, shrimps, polynoid polychaete worms and much more! (as well as bacterial mats growing around the hot water and etc.)

But perhaps MOST impressive was how these vents formed chimneys which took on these very cathedral-like morphologies.

Stunning.

They pretty much spent the whole day going from one chimney to the next..and none were disappointing!

I ran these by some of my colleagues (who are stalked crinoid experts).. and this one for example was described as "totally crazy"

This one was apparently seen before from the Philippines/Celebes regionand was identified as a new genus and species! All we have to do now is to collect it!

5. Impressive Acorn Worms (enteropneusts)Acorn worms are one of those weird groups of worms that have been around for quite awhile and are known to biologists but only recently has there been very good imagery to show off how cool looking they are!

Okeanos saw this one recently, displaying a prolific amount of mucus and a very prominent amount of defecation as it plows through the sediment feeding on the organics!

Here we see mucus with sediment granules as well as poop inching its way long the intestine...

Let's face it, there has been a LOT of amazing stuff on these dives...

Honorable MentionsThis fantastic benthic ctenophore! I've discussed these in many posts before (go here) but this is a bottom living species of comb jelly, which are normally observed swimming...They extend their very LOONG tentacles into the water to feed....One individual measured during the hawaiian expeditions went on for nearly a meter!

This was a mystery. A bunch of soft, blobs. Still not sure what it is (foram? sponge? eggs?)..but enigmatic and intriguing.

This sea urchin popped up during the last hours of the hydrothermal vent dive (see aforementioned vent chimneys). A bit of a mystery....

And then yesterday near the mud volcano, we observed not just this large star-shaped trace mark in the sediment but ALSO this little brittle star!

Note how the disk has a kind of raised dark bump?? That's a feature that is pretty unusual for brittle stars. So possibly in the genus Ophiomyces or something else which could be entirely new..

If so, this would be one of the first times its been seen alive!

Predatory Tunicates!

These are actually Chordates like us, but usually tunicates are filter feeders that pick organics out of the water current..

HERE we have TWO genera of tunicates which have adapted to feeding on other ANIMALS!

This one is called Megalodicopia! These have modified their "in" siphon to form a HUGE mouth. Note the little tube on top?? That's the "OUT" siphon. Water goes, with food and flows out through the top (presumably at a higher pressure given how much narrower it is).

Another stalked predatory tunicate is this one: Culeolus. Same basic idea, except that the feeding bits are on a STALK... Water+food goes in one end and out the other!!

and of course, this beast! yeah, yeah, the jellyfish, Crossota sp... always a crowd pleaser!

In other words, Tim identified, requested and/or otherwise retrieved THOUSANDS of records of brittle stars! When you consider how MANY specimens of ophiuroids there are? That is a HUGE effort!!

Based on this analysis of species records correlated with different habitats, especially across different depths, they were able to determine several broad based and IMPORTANT patterns about WHERE brittle stars occur..

Deep-sea species diversity is shaped by energy availability (i.e. thermal energy and nutrients)

Continental shelf to upper-slope species richness consistently peaks in tropical Indo-west Pacific and Caribbean (0–30°) latitudes, and is well explained by variations in water temperature.

In other words, warmer water (heated by the tropics) promotes greater species richness.

Deep-sea species show maximum richness at higher latitudes (30–50°, i.e. polar regions), where they are concentrated in areas with high carbon export flux and regions close to continental margin (richness drops as you get away from the land).

The yellow and red in the diagram indicate species richness. These are warmer areas with relatively high nutrients, etc. As the colors fade to purple and blue we see those numbers

decrease on the broad abyss of the ocean floor.

Data are consistent with a hypothesis that deep-sea species richness is maintained by species migration from shallower regions. i.e., "high energy areas feed low energy areas"

Historically we have looked at tropical areas as the focus of conservation efforts, but if we TRULY want to conserve deep-sea habitats we will need to consider the areas which show DEPENDENCE on the shallower regions for diversity.

If this is the case, then our conservation efforts will need to focus on MORE than simple high species diversity. We'd need to further look at places which are DEPENDENT on diversity!

In some ways, brittle stars are one of the most important "model animals' to observe these trends and interactions. Why?

1. Echinoderms, including brittle stars live ONLY in the oceans. No freshwater, or land relatives.

2. Brittle stars are EVERYWHERE. They are one of the most numerically abundant groups of echinoderms known.

This paper is the latest "big thing" to come out of Dr. Tim O'Hara's echinoderm lab at the Museum Victoria!

The Nature paper is sort of the "other shoe" that has dropped with big discoveries. (Remember thatechinoderms have five shoes!)Dr. O'Hara's other BIG news in recent years has been the announcement of this: a comprehensive family tree of the ophiuroids!

The Brittle Star Phylogeny Project

One of the most important and fundamental elements of biology is understanding the evolution and relationships of your study organisms.

How are all the different groups related? (e.g., how are basket stars related to other brittle stars?)

How did they diversify? Where?

What kind of habitat did they diversify into?

Which brittle stars form actual, NATURAL biological groups?

A phylogenetic tree helps to answer all these kinds of questions!

In biology, a well-supported tree with a strong data set supporting it is BIG DEAL. You can literally put ALL the information known about a group, in this case-the brittle stars, into a PROPER evolutionary framework!! Perhaps some lineages share a particular ecological nice mirrored by body form. A tree like this can literally be mined for information for years.

This starts with such immediate things as classification and rearranging all the families to reflect "natural" groupings. In other words whether taxonomic groups such as families or genera-created by scientists based on external characters are "real" or perhaps the result of misleading external appearance. At some point, there's probably a whole POST about that topic!

This kind of data is a POWERFUL statement.

Genetics is powerful stuff. Work on the "Big Tree" of ophiuroids suggests that there are many, MANY more families and SEVERAL orders of magnitude more SPECIES.

Past accounts have estimated about 2000 species? In fact there are likely several TIMES MORE than that. But the exact number remains to be seen..

The work from Tim's lab has nearly DOUBLED the number of recognized FAMILIES of Brittle stars!

He's also turned the classification of these animals on their head! some of the oldest known species turn out to be these interesting deep-sea forms.. Ophiomusium and their relatives! Many surprises!

As many of you picked up on last week, I've been busy working on starfish at Museum Victoria in Melbourne working with my colleague Dr. Tim O'Hara, one of the world's leading authorities on ophiuroids! aka the brittle stars and basket stars!

While talking to Dr. O'Hara he informed me of of some neat, NEW SPECIES he's described from the deep-sea habitats of the South Pacific New Caledonia in late 2015! These were just too neat to pass up a post on!

1. The Impeller Brittle StarAs Dr. O'Hara tells the story, he was once called upon to aid a ship's engineer during his attempted crossing of the Bass Strait on the yacht Irene. A similar looking impeller failed the yacht's engine thus indelibly impressing its shape onto his mind's eye!

Fast forward many years.. and Dr. O'Hara is describing this new amphiurid brittle star from the deeps of New Caledonia.

The large shields on the disk trigger a memory that reminds him of the impeller's shape! and voila! Enter: Ophiodaphne impellera

2. The Game of Thrones Brittle Star: Ophiohamus georgemartini!!Probably the most STRIKINGLY amazing brittle star Dr. O'Hara described was this one, a new species in the genus Ophiohamus (family Ophiacanthidae), collected from a depth of 275 meters off New Caledonia!

Here's a nice shot of it holding onto this sponge stalk... Note that its most striking feature? Those big crazy spines that are coming off the disk!

If we take a closer look at those big thorny spines coming off the disk...

and compare them with the sharp thorns coming off the crown depicted on the cover art from Game of Thrones: CLASH OF KINGS! This provided the inspiration for the Species name for THIS new species of brittle star!

BOOM! Tim named this one in honor of the AUTHOR of one of his favorite shows: GAME OF THRONES!!

Ophiohamus georgemartini!!

3. Ophionereis sykesi(family Amphiuridae)in honor of his wife who as Tim O' Hara put it "has had to put up with him rummaging around the world's museum collections for years"

An animal with a gorgeous disk plate field which I'm sure is a fitting honor for the Mrs!

4. And finally, Amphipholis linopneusti, described by Dr. Sabine Stohr in 2001.

NOT a new species but an interesting one from the New Caledonia region in that its one of the few echinoderms that I know of which is actually sexually dimorphic! That means there are actually ways of determining males from females using external characters!

The lowermost basal arm spines of males are enlarged, sometimes flattened and hour-glass-shaped, whereas on the females they are cylindrical with a blunt rounded apex. Its a subtle difference to be sure but it exists, which is more you can say for a lot of echinoderms!

In the same way that a particular class of echinoderms is made up of diverse members, so are the research labs which study them! So, in my last installment of #EchinoblogInAustralia I thought I would do a brief profile of researchers doing various kinds of echinoderm research at Museum Victoria in the Marine Zoology Department!

Just as a refresher though.. Here's a pic with the BIG project that Tim O'Hara's lab has been working on for the last several years: the BIG ophiuroid (aka the brittle and basket star) phylogeny! aka the "family tree" of the ophiuroids!

As I've mentioned previously, the new phylogeny is a BIG deal. It involves a group with over 2000 species which has been a taxonomic headache to scientists for over 100 years. Their research has literally turned this whole field on its head! (if brittle stars had a head!)

The tree clarifies which groups show support for being "real" and elaborates on how different brittle star and basket groups are related to one another. It will almost DOUBLE the number families!!!

The tree itself is HUGE. Here it is below printed out and mounted on the wall for easy reference. You can see that it extends from that lower bookshelf to the that top shelf-so the printout is easily 6 feet tall (or two meters)!!

Dr. Hugall worked on the analytical aspects of the project and, in conjunction with Dr. O'Hara, cleaned up the genetic data in order to make it ready for analysis. He also provides a good complement to the "natural history" side of the lab with a powerful analytical background.

2.LupitaBribiescaLupita is a PhD student at the University of Melbourne and got her undergraduate degree from the Universidad Nacional Autónoma de México. She's not only very proficient in computer coding and analysis but she's already a prolific author in echinoderm systematics! Especially in anchialine cave echinoderms!

In Mexico, Lupita worked on echinoderms which lived in submarine caves fed by the ocean. Some of her work can be found

Since then Kate has received her PhD and continued to do her awesome work combining ecology, taxonomy and molecular phylogenetics at Museum Victoria.

These days she's been working a LOT on feather star (i.e., crinoid) taxonomy and diversity in Australia. It turns out that there's a LOT of these in Australia that remain to be discovered and what's known requires a lot of work.

As with many of us, she seeks a good job, funding for her research and all of life's finer things!

She HAS however also been working on new species of brittle stars in the genus Ophionereis!

photo by John Keesing

5. P. Mark O'Loughlin and Deep Sea Sea CucumbersOne of the most established echinoderm researchers at Museum Victoria was actually Tim O'Hara's original mentor!

Aristotle's Lantern is this weird yellow piece in the picture below. These sit over the mouth opening and the "teeth" or jaws of the sea urchin emerge through the bottom..

This illustration gives you an idea of the orientation

And here's a video that allows you to see the teeth emerging through the oral opening and back again.

Urchins use these teeth to rasp algae and other food off the substrate. They are quite effective when one considers just how much algae a sea urchin eats!

ALL of the stories below are part of a field known as biomimicry!Basically, taking the idea/engineering from ACTUAL biological structures that have demonstrated effectiveness and reverse-engineering them so that they can be used in industrial or other applications!! Urchins have been quite the inspriation of late! Here's a round up of some of the recent and more interesting ones!

Here's an Italian "bionic model" of how the Aristotle's Lantern jaw might work.. Kind of similar to the way a claw in one of those arcade "grab claw" games works!

3. Architecture: Urchin Test Shape distributes Stress!

Its been commented upon at sites such as these that the "oblate" shape of sea urchin skeletons (i.e., the test) is very effective at distributing stress evenly over the surface. Thus, the shape of urchin skeletons might actually be useful for inspiring better shapes in building!

But what are some of the more SPECTACULAR animals they have been seeing?? Here's a highlight of the ones I consider just singularly amazing!1. Big White Lyrocteis-like Benthic Ctenophore (aka comb jelly)The last year or two has seen a HUGE awareness of these strange animals. Basically they are the bottom version of swimming comb jellies aka ctenophores. Although gelatinous, they are possibly VERY distinct from proper jellyfish.

This newly discovered white animal has a very different surface texture and so far has NOT been observed to extend its feeding tentacles! It has the same "rabbit ears" or "harp" shaped body as Lyrocteis but is it even the same thing?? Interesting!

2. Stunning sea anemone in the family Aliciidae!

This one was just stunning and weird all at the same time. It kind of looks like a strange gelatinous Christmas Tree! From Ahyi Seamount, 275 meters

Fortunately Dr. Chris Kelley of HURL had seen one of these before. The withdrawn version of a seldom seen sea anemone in the family Aliciidae.

Here's a picture from the HURL database showing it extended. You can see the knobs on the body. Beautiful..but wow. Unusual.

3. The Sea Anemone (from) Liponema! ANOTHER bizarre sea anemone. These go by the common name "pom pom anemones" or "tumbleweed" anemones... Why? Because they actually have a very loose connection to the bottoms and can actually ROLL along when they want to move!!

This pic from Pagan Volcano and Supply Reef from about 336 m

Here's a separate species called Liponema brevicornis doing JUST that thing! Rolling along the bottom like a big pink fuzzy snow ball!!

7. And some New Species of Snails...This is what's called a slit shell snail or a member of the family Pleurotamariidae. Long story short: deep-sea snails but with similar shells observed in the fossil record. This gives them "Living Fossil" status and their beauty and color makes them valuable to shell collectors..

The one the Okeanos Explorer has been seeing? Probably a new species according to Chong Cheng at JAMSTEC (@squamiferum on Twitter).

Those yellow balls on the body extensions? Apparently those are luminescent organs! Not previously seen in this genus..making this a very likely NEW species (thanks to Dr. Gosliner for the determination!)

July 1st, every year is now recognized as INTERNATIONAL POLYCHAETE DAY in honor of long-time and widely loved polychaete worm expert, Dr. Kristian Fauchald's birthday! Dr. Fauchald passed away in April 2015

Among the points I made? that many polychaetes are actually named for greek nymphs, goddesses and other mythological characters!! Today.. I focus on that topic and share the etymology of some awesome looking polychaete worms!!

5. AphroditeProbably one of the first polychaete worms I was able to recognize on sight was this gorgeous animal! Also known as the "sea mouse" the genus Aphrodite described by Linnaeus in 1758 is arguably one of the most distinctive of marine invertebrates.

It is of course named for the famous Greek Goddess of Love, Beauty and Sex. But I suspect what made her name particularly apt, was that she was born from the foam of the sea (aphros).. the complete name Aphrodite means "Risen from the Foam"

Its many iridescent bristles and unusual shape have made it one of the more memorable animals to encounter in an Invertebrate Zoology laboratory or field trip. These and the various members of this family (the Aphroditidae) occur primarily in cold-water habitats and can be encountered in a wide range of habitats, from SCUBA diving to bottom trawls in the Antarctic!

And is any animal more deserving of the name? Stunning.

4. ChloeiaPerhaps one of the most strikingly beautiful fire worms (a type of polychaete with very inflamatory setae) is named for the female name Chloe. Given that the name was assigned by none other than the famous French naturalist Lamarck in 1818, the name may be in reference to Chloe from the Greek story Daphnis and Chloe

Chloeia is a worm with large, colorful bristles and occurs throughout the tropical Atlantic and Indo-Pacific, certainly the beauty of its namesake!

Images of "Chloeia flava" are seen commonly on various image and video websites. Its not clear if these are all correctly identified, but they DO show a wide range of colors and patterns!!

3. Swima & Flota

The "truth in advertising" award for polychaetes (in the Accrociridae) goes to these two pelagic worms with names that essentially DESCRIBES their life style! So, for Swima, was named for that species ability to SWIM.

The genus name Flota would seem to similarly suggest "float" in Latin..

Disclaimer: Statue of a generalized classical nymph intended to represent concept and NOT a statue of Syllis!

Syllis and all of the members of the Syllidae are quite gorgeous polychaete worms and its not hard to see how Marie Savigny and Lamarck saw fit to naming them after a Greek naiad!

1. All the Worms named for Kristian Fauchald! International Polychaete Day honors Dr. Kristian Fauchald, but EVEN IF the event were to pass, his name has been immortalized into the polychaete literature!!

Based on a search of the WoRMS database (World Registry of Marine Species), as of this writing, there are approximately FORTY polychaete worms which carry the name "Fauchald"!!

Most are species epithets but there are at least TWO genera, Fauchaldius and Fauchaldonuphis!

Sadly, I could not locate any living images, but here are diagnostic diagrams of species named for Dr. Fauchald!!

Here for example isAmphisamytha fauchaldi which was a new species of ampharetid (Annelida: Polychaeta) from the hydrothermal vents at Guaymas Basin, Mexico. Over 2000 meter depths! (as one would expect for a hydrothermal vent species).

Perhaps one of the most significant losses following the massive starfish wasting disease epidemic that hit the west coast of North America (and possibly parts of the east coast) was the apocalyptic loss of the iconic sunflower sea star, Pycnopodia helianthoides.

When I was growing up on the west coast, there were sunflower stars that were HUGE!! Tall tales would report them reaching two and a half, then THREE feet across! But most were a good dinner plate size.

Sunflower Stars are an ecologically important species. Unfortunately, populations of this species were DEVASTATED by the starfish wasting disease epidemic. More so than almost any of the other species, the sunflower stars were more often than not, completely removed from local areas along the coast.

The exact reason is not clear. Possibly because the sunflower stars are not around? and the animals have just come out of hiding? Or have the stars been controlling the population structure of the urchins? But it DOES seem to be related to the absence of the once abundant and mighty sunflower stars.

But Sunflower stars are also an ICONIC species..

In addition to be an ecologically important part of the intertidal and subtidal ecosystem, there's a lot to be said for how they really represented the North Pacific. Pycnopodia is an endemic, found nowhere else in the world.. and was often used as an example of the special and diverse fauna on the west coast of North America..

Some of the individuals which had been on display in public aquaria died within days. Some of these individuals had been around for over 20 years. Suddenly? Gone.

Those of us who are most familiar with the West coast fauna.. divers, naturalists, scientists, citizen scientists, beach goers, students, fishermen, anyone with an intertidal or subtidal ID guide was suddenly NOT seeing this species. It was and still is a significant and sad loss.

And so.. observations of THIS species have had a SPECIAL significance..

BUT today, a colleague of mine, Ms. Brenna Green observed THIS. A juvenile Pycnopodia helianthoides in Northern California!! According to her, one of the first she's seen in a good long while!!

Here's one of the most critical parts of these observations: Most are consistently SMALL. Many of the "adult" individuals we were used to encountering were easily dinner plate size or larger have not really been encountered.. or if so, not regularly.

Are the small sized ones a sign that they simply grow very slowly? Or more ominously, do they die as they reach a certain size??

On the upside, I have heard SOME anecdotal observations of adult (~40 cm) sized individuals being seen in Washington and in other localites...

A happy July week to all of you! So, as we enter into the lull of the summer I present to you some choice Echinoblog image and video picks from various image streams that show off one the internet's most frequently photographed sea urchins! The diadematid ASTROPYGA!

Astropyga also appears to have a rather painful array of spines but I'm unsure if these pack quite the toxic wallop that Asthenosoma does..

Astropyga includes four known species, one in the tropical East Pacific and another in the Indo-Pacific and two in the tropical Atlantic. All are known to occur primarily from relatively shallow to mesophotic depths as we saw recently on a Bishop Museum expedition to the "Twilight Zone" (here)

But even within the widely occurring Indo-Pacific species. A. radiata there appears to be quite a bit of color variation from the dark colors seen below to the lighter ones like this

The genus name can be broken down to "Astro" meaning star and "pyga" which refers to rump or buttocks.. so the name literally translates to "Star Butt"!!.

Why? Well, you see this giant bulb on the surface? That's an extension of the intestine called the anal sac. That's where the POOP comes out! I've talked about that here. So, basically some wry taxonomist looked at the anal sac and the pentagonal symmetry and decided "yes. The STAR ASS!"

Flickr and Youtube are GREAT for picking up on natural history observations. Yes, there's always the lack of scientific rigor but sometimes divers just make simple observations. And THAT can be the start of knowledge.

All the images below are probably A. radiata from the Indo-Pacific.

Astropyga scavenging on dead fish!(Lembeh)Based on a round up of papers I could locate, A. radiata has been reported primarily as a scavengers, feeding on algal debris and other stuff from sediments, etc. But if this image is accurate (and not posed) they occasionally much on dead fish as well. This is actually consistent with other sea urchin feeding habits, so I feel comfortable in presenting it here..

Blue Iridescent Spots! Its been speculated that these are photoreceptors but they've not been tested and its unclear exactly what their function is.. But they immediately stick out when observed on an otherwise bright red sea urchin!

Spawning!This speaks for itself.As with other echinoderms I've shown here (such as the sea cucumbers) just because you see white fluid being emitted its not actually clear what sexes of the species are present. The fluids likely represent BOTH sperm AND eggs.

Sometimes this species form large aggregations, which are most likely to help facilitate their reproduction and sexy time!

Astropyga moves surprisingly quickly!While I haven't actually seen one of these alive and close up, its pretty clear that even for sea urchins they are capable of a surprisingly brisk sprints! and across some unusual terrains to boot! That's quite a lot of coordination of spines and tube feet at play..

here's a bunch of them in what looks like a mating aggregation, moving en masse!

Sea urchins are basically big spiny balls that seldom move and surprise! surprise! There never seems to be a shortage of OTHER, smaller animals that can take advantage of this as "habitat."

Crab Commensals! These don't seem to be as bad as the crabs on Asthenosoma, (the proper fire urchins) simply because these don't seem to "dig" themselves into the urchin surface. Spines on Astropyga seem long enough to provide adequate protection as-is...

and vice versa?? Probably one of the most unusual things I've seen imaged by divers since Flickr and YouTube became a thing has been this.. Crabs in the family Dorippidae that PICK UP urchins, sea anemones and carry them on their carapace in order to use them as sort of a defense as they walk along the sea bottom.

Today as I was scrolling through the many years of posts I realized that I have NEVER written about the Crown of Thorns starfish, Acanthaster planci! If you don't live in the Indo-Pacific you might not realize that this is actually one of the most heavily studied starfish in the world! There are whole BOOKS written just about the biology and ecology of this single starfish species!

Why? What makes this species so important?

This starfish is a voracious coral predator! It just extends its stomach onto the fleshy tissue of a "hard coral" (i.e. scleractinian) and a little while later, only the "cleaned" skeleton of the coral remains!

If it was a reasonable number of these animals feeding on coral, it would actually be healthy for the ecosystem. Predators control community structure and are important to ecosystem function..

The thing is though that this species, for reasons which have been studied since the 1960s, have undergone sporadic and localized HUGE population explosions! Their incredible abundance results in the wholesale LOSS of complete coral reefs!

Image from Wikipedia, taken by Jon Hanson, in Thailand: https://en.wikipedia.org/wiki/Crown-of-thorns_starfish#/media/File:Crown_of_Thorns-jonhanson.jpg

Here's the thing though. In spite of all the hate that gets laid on these animals.. I STILL think they are kind of freakin' AMAZING!

So, today, I thought I would exploit the wonderous world of Flickr and show off some of these spectacular macro shots displaying the surreal surface of these animals...

The crown of thorns occurs across a WIDE range. From Baja California to Hawaii and Japan and then down to the east coast of Africa in the Indian Ocean. The range of colors is similarly vast! Its not entirely clear if these might represent separate species or perhaps represent some other kind of variation based on the environment. Perhaps food? growth? Difficult to say...

But genetics DOES indicate that there are multiple "cryptic species" across this animal's wide range in the Indo-Pacific..

The big thorny bits are of course, the spines.. the dark dots on the surface are the papulae (or gills) and if you see little white or dark beak like structures, those are called pedicellariae whose function in these animals is not entirely clear... But likely some kind of "in close" defense against parasites or what have you....

and the ANUS of course! That's the dark spot, probably surrounded by spines... this shot is nice because it not only shows off the papulae (the gills) but also the pedicellariae (the red tweezer like structures)

As one finds often time in nature.. you have some big animal with lots of complex surface textures.. so are there animals to take advantage of it! Shrimps often live closely and among the spines on the animals' surface...

here are tiny shrimps.. some in the genus Periclimenes...

And the ORAL surface!Strangely enough, the top surface of Acanthaster is remarkably well known but how many people have actually seen the ORAL surface where the mouth is???

In addition to the tube feet all converging at the mouth, you also see the oral spines projecting into the mouth itself!

and in this one, you can actually see some of the cardiac stomach below the purple spines...

And a video to top it all off!

At some point, there will be much, much MORE about the Crown of Thorns!

My first exposure to LIVING Hymenaster was back in 2001 when I was working with Craig Young on an expedition to study glass sponges in the Hawaiian Islands (see pic above)

I got an opportunity to collect a bunch of deep-sea asteroids at that time and saw my FIRST deep-sea slime star!!

and a few minutes after, I discovered for the first time that, just like their shallow-water cousins, Hymenaster could emit mucus just as effectively!! In other words SLIME!

Image by H. Reiswig.

Hymenaster is a WEIRD animal. The entire surface has evolved into a strange soft covering, This varies in different species. In some the body is membranous and kind of leathery, others, sometimes soft and in others, almost completely gelatinous. In those latter gelatinous species, almost the entire body, save for the tube foot grooves, mouth frame and various other structures are nearly all soft and squishy. Very little in the way of "hard parts"

The name Hymenaster translates from the Greek into "Hymen" and "aster" or "Membrane Star" which as we shall see is pretty fitting.

The body is almost transparent. You can see the five radiating tube foot grooves plus the mouth and some spines and etc. in the surface areas which you can sort of see through.

Hymenaster sp. from Maro Crater (Hawaiian Islands)

Hymenaster's translucent body draws an analogous comparison with many deep-sea sea cucumbers such as this one observed at 4800 m in the Hawaiian Islands... So perhaps there is an adaptive advantage to having this gelatinous body wall?

Hymenaster occurs all throughout the world: Atlantic, Pacific, Arctic, Indian and Antarctic (i.e. the Southern) Ocean. The genus includes approximately 60 species.

The problem with many of these deep-sea pictures is that the diagnostic characters used to ID them are from characters that are either on the underside, along the tube foot grooves or actually INSIDE the body. Color, shape and surface texture all seem to vary..so it can be difficult to "nail down" which species is which..

Unfortunately, these animals don't hold up well after collection. Here's one after the delicate touch of a robot submersible. Think about what what a delicate animal like this looks like AFTER a trawl net has dragged it for about an hour on the sea bottom!

It depends on the species of course, some of the tougher species are pretty tough. This one looks like its in pretty good shape. Still weird but the features are all there...

One of the most complicated aspects of studying these animals is "matching up" the examined, often damaged specimens from above with the living animals. And lately there have been a LOT of images of living animals!

There is nearly NOTHING known about the biology of these animals. What do they eat? What is the slime used for? What is the gelatin-like body an adaptation for? Where do the species live? Are they separated by depth? How have they evolved?

ALL of the observations below have screengrabs via the Okeanos Explorer program!!

PACIFIC OBSERVATIONSThe deep Pacific is a VAST area. Images below are mostly from North Pacific observations..undoubtedly there remain many MORE species further south.

A Pink One from the southern region of "Bank 9" in the Hawaiian Islands region

here was an ENORMOUS one from the Hawaiian Okeanos that was HUGE about 20 cm across!

This one nicely illustrates the osculum, which is that big center hole on the surface which is how water enters the cavity surrounding the body surface thus bringing water/gases to the papulae (i.e. the gills) within.. It gave us a nice show with its opening and closing osculum!

This is what I previously identified for HURL as H. pentagonalis..but it doesn't seem to match the orange one at the top of the post above in terms of color or texture. So, possibly something else.

From East Necker Seamount in the Hawaiian Islands region. A different color from H. pentagonalis.

and yet ANOTHER Hymenaster species (I think??) from Salmon Bank in the Hawaiian region. White with flyffy surface texture!

A recent image of Hymenaster sp. from McDonnell Guyot in the Wake Island region. Same genus but the surface texture is VERY different..

Here is yet ANOTHER species from Barkley Canyon off British Columbia.. Again, very different body shape, surface texture and color..

ATLANTIC OBSERVATIONSIts also entirely POSSIBLE that SOME of these Atlantic species might actually be the SAME ones as the Pacific ones.. There are some similarities below with the ones above..

From Puerto Rico

From Atlantis II Seamount (North Atlantic)

From the Atlantic, Mytilus Seamount (via Okeanos). On top of everything else, the surface membrane is "ballooned" up... which is more mysterious behavior.

From Physalia Seamount (North Atlantic). Honestly, this one might be something else entirely. The surface texture is unusual.

These were all taken from images on Flickr, and so the original photographers can be found merely by rolling over the image itself. What's great about them, is that the images were taken from LIVING animals, and so their colors remain vibrant! Nothing here is photoshopped.

GREETINGS! And my apologies for the long silence over the last few weeks: a little bit of time to recharge the batteries and a little bit of frantic insanity as the fall began! So, this week I am back!

There's been a fair amount of news about taxonomy lately, so I thought I would embellish with some "behind the scenes" knowledge that might not have been evident simply from the news reports themselves...

Scientific Names vs. Common or Popular Names: What's Required

Just so that we're all on the same page, here's some general information about the naming of new species.

There are actually a set of internationally recognized CODES (i.e. rules) for describing species and governing their use. These codes are overseen by the International Code of Zoological Nomenclature (here) and although they are not much more than a regulatory organization, they do try to keep everything from going taxonomic kablooey!

Basically, it is these rules that dictate HOW a lot of organisms in the world get scientific names. So, simply SAYING that a new organism is called "A blue Baboo Fish" won't cut it. It actually has to be supported by evidence and published in a PEER-REVIEWED journal and given a proper scientific name in the proper format (in Latin, etc.). ONLY THEN is such a name considered valid.

BUT a number of other rules are also at play in order to keep the process of naming new species orderly...Nomen Nudum aka Why we don't know the name of the President's Fish (yet!)Have you ever noticed that there's often a significant time lag between the time someone ANNOUNCES that they have DISCOVERED a new species and the time that new species is ACTUALLY described??

That's because the name is not "official" until it is actually published in a scientific journal. If for some reason, the name is actually published before the proper scientific documentation is released to accompany it, the name becomes what is called a nomen nudum which is Latin for "naked name."

Note that while some accounts actually went so far as to cite the genus name (Tosanoides) nowhere will you find the FULL name until its published in the literature. Is it a liberal conspiracy? NOPE. Its Taxonomy!

If they actually announced the full species it would create a nomen nudum, which is kind of like the taxonomic equivalent of a time-space anomaly from Star Trek. That means there's a proper scientific name flying around WITHOUT a proper scientific description.

When written out completely, the full format of valid scientific names display a reference to the original author and date of the paper which described it. Thus, the full name of one of my species"Circeaster arandae Mah 2006" refers to a paper in 2006 in which I described the species Circeaster arandae.

Getting back to the nomen nudum however, Note that this does not necessarily invalidate the name. But it does open the name up for other unscrupulous (or unknowing) individuals to inadvertently use the name, thus "taking away" the name from the author's original intent. (or in the worst case, stealing the name from the original author).Another real example...You might have seen this little guy for example. A new species of dumbo octopus that one of my colleagues Stephanie Bush is working on out at MBARI/Monterey Bay Aquarium.

In an interview she alluded to the fact that the animal is SO cute that she might call it "adorabilis." She called it that informally as part of an interview but the media took the name and pretty much made it stick.

SO many news outlets have now used this name that it has turned up everywhere..but it has NOT been described or published in a scientific journal as of this date (Sept. 2016). This is not strictly a nomen nudum but conceivably, someone might mistakenly cite it in a scientific journal somewhere.

If that happens, then BOOM. It has entered the literature. This still does not mean that Dr. Bush cannot use the name..but it DOES mean that if someone else happens to use the species name "Opisthoteuthis adorabilis" that will "steal" the name away from her because ANOTHER scientist will have justified a species using that name in compliance with the ICZN code..

If by chance the name was published TWICE and in proper compliance by BOTH authors then a new situation arises. In that case the name published first has priority... A great segue into a discussion of SYNONYMY...

Synonymy aka Why you have to be careful if you "bought" a new species

Probably one of the most important of the codes in the ICZN is that of "priority" which basically states that the OLDEST (i.e. the FIRST) name established for a species is the correct one. All subsequent names of the SAME species are essentially considered redundant and their use is suppressed once that assessment is made (but there are exceptions on occasion-better explained at another time).

That seems pretty straightforward. But in truth, it can get pretty unfairly brutal.

There's a LOT of new species that are named in "good faith", sometimes even with very strong data that for whatever reason are ultimately deemed to be "redundant" and are suppressed in the literature.

So that means if someone described a new species with a shoddy (or in some cases, almost NO details) description-but it was ADEQUATE, followed by a second description that was just an objectively BETTER account, that FIRST author gets credit and the other species get put into the list of "redundant names" aka the synonymy.

So, someone who is NOT a scientist can easily get the rights to name a new species or even name a new species AFTER you as a gift....but its always possible that the name you give it, whether your own or someone else's, could eventually be synonymized by another person in the future because of some unknown specimen or just better understanding of the species in the future.

Now, granted, there tends to be LESS of a chance of that happening depending on how much work the scientist doing the work has done and depending on what kind of data supported that new species in the first place, especially with molecular data.

But its STILL possible, sometimes even if nothing was done wrong... Science is an ongoing process and although taxonomy has kind of a reputation for being a bit stogy the truth is that it IS quite dynamic and taxonomic changes are common place (much to the annoyance of those who use species names!)

A question that came up recently from my last Okeanos round, was whether or not a new species could be described ONLY from a picture or video rather than a specimen???

Uh.. No and yes.

For MOST (nearly all) cases, some kind of voucher is necessary. Why? Because we require EVIDENCE to describe a new species. Measurements. Observations of the skeletal (or non-skeletal) structure. Analysis of different features. DNA. Any one of thousands of kinds of data which permit us to carefully contrast the known species of organisms from one another.

At the very least, a specimen must be examined so that we can carefully discern why its gross morphology is different from other similar species. These specimens are conserved. They are saved in museums for future generations to reference and retained for hundreds of years.

HOWEVER. In some RARE instances, there IS an allowance for new species to be described ONLY from a picture. It used to be invoked for exceptional cases-rare and endangered species for example.

We live in an era with increasingly high-resolution imagery, sometimes SO good that even the minutest details can be made out without physical examination. Millions of images of a biodiversity survey can be brought back on a drive the size of a large coin.

The conservative scientific approach in publications would be to indicate it IS a new species but without a proper name (e.g., Octopus n. sp. 1)

BUT it can't be properly characterized because a LOT of octopus characters are internal and require direct comparison (unlike the South African bee example above which COULD be identified and characterized).

Also, while unlikely, its POSSIBLE that there is a specimen of this animal somewhere in a museum somewhere in the world which has already been published. Without reconciliation of all these disparate factors, one risks creating redundant names which are essentially permanent and creating possible confusion.

Thus, identifying a species directly from ONLY a picture would be more direct but not as thorough and does not give us enough data to properly assess it. But yes, there are exceptions.

Identifying species only from pictures also invites the possibility of abuse and reckless taxonomy which could impede and hopelessly confuse the work of legitimate scientists during a time when there is a dire need for workers to be be studying Earth's biodiversity...

Species named after celebrities & pop culture? What's up with that?

from http://novataxa.blogspot.com/2012/10/2012-yoda-acorn-worm.html

Scientific names as outlined in the Zoological codes are always supposed to be in Latin. A dead language that nobody speaks any longer. This used to be a scholarly language that was widely used among educated people.

Most scientific names are based on descriptive terminology. So, for example, the name Acanthaster , which is the scientific name of the Crown of Thorns starfish (learn more about this genus here),literally translates into "thorny star" from the Greek acanth- and the Latin -aster meaning star. Many of these names were sort of an open book...

Although you would think that naming a genus would be better than a species (because a genus is higher up in the taxonomic hierarchy), in fact, its not. Higher level names tend to be made into synonymies more frequently than species. Species tend to stick around for quite awhile longer..

As we have gotten into the 20th and 21st Century however, we NOW see increasingly the role of pop culture influencing taxonomists! There are a number of reasons: Some think it makes taxonomy more relatable, some have found genuine inspiration from popular entertainment, others have many MANY species and have just "run out" of Latin names.. an endless list from a huge pool of scientists.

Sometimes the people/characters as names are directly influential! As with Yoda above. the genital flaps of that acorn worm (an enteropneust) were VERY reminiscent of Star Wars Jedi Master Yoda! The ICZN is actually surprisingly flexible in allowing for "translating" terms into taxonomic names... And hence its namesake! From a character created in the late 20th Century into an ancient dead language! No problem! (if you know how)

Taxonomists are diverse. No longer done by ONLY classic stodgy, out of touch scientists-but hip, trendy nerds as well! .. it is done by many students and dynamic individuals who follow popular trends.. and we will likely see more and MORE of these pop culture names in the future....

thanks to Monica M. who asked me the question about Obama's fish! that inspired this post.

Here's some video to give you an idea of what it looks like/how it moves, etc. (I would watch without sound to enjoy the zen of the animal)

IF the name doesn't sound familiar, the animal's distinctive appearance definitely stays glued in your head after you've seen one! Imagine a big blobby sea cucumber with what looks to be a HUGE LOBE sticking out of its hind end!

Note the image above contrasted to this diagram showing mouth (top) and anus end (with lobe-bottom).

The genus Psychropotes is derived from the Greek for Psychros which means "cold or frigid" and "potes" which honestly, I could not find a definitive translation for... One root translated to "flight"? possibly alluding to the ability of this species to swim...And another colleague tells me it might mean "dweller". Ah well, one mystery at a time!!

Psychropotes includes 11 species which occur widely, all around the world in the Atlantic, Pacific, Indian and Southern (but not in the Arctic) oceans in the deep abyss of the world's oceans! That means roughly 2000 to 6000m. They are the deepest of the deep! Considered "classic" deep-sea inhabitants they were collected and described from the HMS Challenger's historic mission.

These can be pretty BIG animals!! as this image from a recent MBARI expedition demonstrates. (with deep-sea biologist Greg Rouse for scale!)

From MBARI https://twitter.com/sarahkeartes/status/593979334056022016

But there is ONE species in particular, P. longicauda (the species name "longi-" means long and "caudex" refers to 'trunk or stem" and alludes to the posterior lobe in the same way that caudal fin refers to the end of a fish) that is of interest.

Individuals all identified as this species, P. longicauda have been observed from oceans all around the world and varies rather widely in many ways. Sea cucumber species are identified based on tiny calcite bits called sclerites which seem to be highly variable.. with differences in sclerite shape varying between different regions. But do all of these differences amount to different species? Or variation within ONE species??

Here for example was one seen from the recent tropical Pacific Okeanos Explorer cruises. Note that the "lobe" is a different shape. Separate species? Damage?

This turns out to be a pretty important question to deep-sea biologists. Can there be ONE species present at such a huge scale? Or are there species present that are CRYPTIC or hidden from us by body characteristics alone???

Note the one above with the shorter, forked "lobe" Is it the SAME species as the purple one shown earlier? Is this variation? (such as what we might see in humans who live in different parts of the world) Or are these separate species?

Their study explored the widespread occurrence of this species based on 128 specimens of Psychropotes longicauda collected from THREE different oceans over a 34 year period, from 1977 to 2011!

This represented an INTERNATONAL team of experts from not only the University of Southampton in the United Kingdom but also the Shirshov Institute of Oceanology in Russia, the American Monterey Bay Aquarium Research Institute (MBARI), Scripps Institute of Oceanography and many, others!!

They sampled tissue for two genetic markers (COI and 16S for those who need to know) across all the sampled individuals in order to compare populations from all around the world.

The Global Colors of Psychropotes!

So, here's the result. Scientists use diagrams to show a basic outline of relationships between different populations. Roughly speaking, the greater the distance between the circles the larger the distance between the populations and the greater chance they are separate species...

In the first diagram, the LARGER the circle, the larger the sample size. So the bigger circle represents the largest number of samples. Which were all from the Atlantic Ocean.

Note the helpful color key so you can tell apart the populations you are seeing below:

Dark Blue= North Atlantic (east)

Light Blue= North Atlantic (west)

Yellow= South Indian Ocean

Green= South Atlantic

Red= Northeast Pacific

Dark Purple= Northwest Pacific

Pink= South Pacific

Their figure 2 here shows what is basically the number of "steps" away from one another each population happens to be... The size of each circle represents the sample size. The big patch of BLUE reflects the LARGE sample of ATLANTIC specimens..but note how they are all clustered together.

Some closer, some farther away.. This means they are all more closely related to one another than to those the others. But note how many different subgroups are present away from the big blue circle in the middle? That suggests lots of

The Red (Northeast and Northwest Pacific) therefore seem to display a somewhat closer relationship to those in the North Atlantic than to those in the Southern hemisphere (yellow, green, pink, etc.)

Figure 2 from Gubili et al. 2016

Their figure 3 below, shows all of the populations in more of a "family tree" (i.e. phylogenetic) perspective..so, not only do we see that all of the Atlantic and Pacific members are "close" but they all occur on a single lineage, which means they were all MUCH more closely related

Two major lineages are most evident in the phylogenetic tree below, Lineages 1 and 2 each with subgroups: Lin 1A, Lin 1B and Lin 2A and 2B, respectively.

The pattern is kind of unclear..but there's definitely an Atlantic cluster (Lineage 2) with members that occur in the Indian and Pacific but this seems very separate from the Lineage 1 which seems to include members from all over, including the Indian Ocean and the South Pacific.

Figure 3 from Ghibili et al.

Ultimately, the two lineages (Lineages 1 and 2) showed > 5% divergence from one another. When compared with other echinoderm species, that much population genetic divergence is enough to recognize a separate species (as opposed to simply a population with structure).

So, YES. One lineage, is the "proper"Psychropotes longicauda species, but there's at LEAST one more which has been "hidden" by the taxonomic definition of Psychropotes longicauda. That is, they all LOOK like the described species but in fact, the differences are FAR more subtle than we had previously recognized! More diversity (i.e., further species) will likely be discovered as more data is collected..

Some of these further subgroups will be so-called "cryptic species" because morphology does not immediately distinguish them. Thus, their status as species is "hidden" by external morphology (but subsequently discovered by genetics). But now that we are looking, many, MANY more characters that could help distinguish these species could conceivably be discovered.

Other Interesting Observations/Questions..

One interesting factoid was that Psychropotes, and many other deep-sea sea cucumbers only occur in areas of high productivity (i.e. marine snow). Could these nutrient rich regions be related to speciation? and diversity within the species?

The authors were able to note changes in the genetic diversity and abundance of the Atlantic lineage across a temporal series! Based on the extensive collections at the National Oceanography Collection at Southampton University, they they observed an uptick in the abundance of small individuals but also a change in the amount of genetic diversity in relation to an increase in organic flux called the "Amperima Event" in 1996!

They found that there were MORE individuals which belonged to the "Atlantic population" and fewer of those which shoed affinities to other oceans. This might explain why the Atlantic "genetic type" was so well established. They cautioned that although they didn't have enough of a dataset to show changes over time, they DID say that there WERE changes in the genetic makeup related to the nutrient availability.

That is a pretty snazzy thing to record from a collection of deep-sea sea cucumbers!

Is there an Antarctic origin for Psychropotes longicauda?

The authors argue that the combination of Southern Indian Ocean lineages was consistent with other hypotheses arguing for an Antarctic origin for this widely occurring deep-sea sea cucumber.

Repeated colonization events from the Antarctic via the Southern Indian Ocean (yellow colored in the figures above) might explain the many lineages of Psychropotes present throughout the world's oceans as well as the presence of multiple lineages of Indian Ocean Psychropotes versus the derived and consistent clustering of Atlantic and Pacific populations.

(Coincidentally this picture of a Southern Atlantic Psychropotes is yellow!! )

http://archives.starbulletin.com/2007/06/24/news/story02.html

What further mysteries does Psychropotes have in store? I anxiously await the next paper! ....now if I could only figure out what the "potes" part of Psychropotes means!

And just because, here are some FANTASTIC Psychropotes Bonuses!

Here was an AWESOME Psychropotes cake by Elizabeth Ross, one of the authors of the study...

This week. Something a little different. I was doing a short presentation for some colleagues about using social media next week and I began accumulating Invertebrate Zoology accounts on Twitter... which at one time were quite rare and realized that it would be a good thing to share all of them.

It surprised me that SO MANY have since become established. I remember many years ago when it was less than 6 people and most of it was secondary to blogging!

Now, not ONLY are there many, MANY IZ Twitter themed accounts specializing on specific taxa, there are actually REGULAR twitter events...

So, here we go. All said and done a list of about 65 IZ twitter accoutns! A list of all the accounts I could locate which focused primarily on Invertebrates, exclusive of insects and arachnids. Yes, sorry land-based arthropods but you are a whole thing all on your own.

This will be a fairly subjective list-I focused mainly on marine groups and those with academic or otherwise focused content that I thought was appropriate. Activity was also a consideration. Some accounts looked essentially inactive and were not included.

Let me clear that there are a LOT of accounts which have a broader focus that regularly include Invertebrate Zoology themed tweets, including aquariums, natural history museums, etc. and frankly those have so many followers its unnecessary to give them much more publicity anyway..

There were MANY, many individual accounts of photographers, naturalists, educators, scientists, etc. who for one reason or another I just couldn't include for the sake of space, focus, etc.

And there are some topics, for example about coral reefs, there's a TON of coral-related accounts and I simply could not list them all... A search on Twitter's search engine will get you all of those names pretty quickly though.

So, please don't take an omission as an offense. In fact, if you've got an IZ twitter account that you'd like me to know about, please let me know and if I think its appropriate, I'd be happy to include it.

You may recall back in 2009 when I accompanied the Monterey Bay Aquarium Research Institute (MBARI) on a 10 day cruise exploring the North Pacific on the Juan de Fuca and Gorda Mid Ocean Ridges off the Oregon coast.Here was the cruise website.I blogged about it here.

When we returned from the expedition I was VERY excited because we had collected MANY specimens and several were either new records of rarely seen species or outright NEW species!

One of my favorite undiscovered starfish was this one, Paulasterias macclaini which I had to describe a whole FAMILY and genus in order to accommodate it! This species was named for Dr. Craig Macclain, at Deep-Sea News, who had invited me on the cruise.

The starfish I reported on in my Zootaxa paper are members of the Goniasteridae, the most diverse family of sea stars, which includes over 260 species in 65 genera! Most goniasterids live in relatively deep-water (continental shelf and deeper) but historically, there haven't been many of them known from abyssal and lower bathyal (i.e., >1000 meter) depths.

Only recently have we been seeing better collections of these animals from these depths. As I've reported below, some were collected from below 4000 meters!

Sibogaster nieseni! The first few specimens of this species were collected by the Monterey Bay Aquarium Research Institute from Taney Seamount (off the coast of San Francisco) from abyssal depths (over 3000 meters!).

It is named for one of my former advisors from San Francisco State University: Professor Tom Niesen (now emeritus)! Author of the Marine Biology Coloring book and noted intertidal naturalist/ecologist along the California coast!

He gave me my first shot at grad school and happily, his advice and instincts correctly guided me through my early years as a Masters degree student!

photo by J. Sharei

It seemed VERY appropriate to name this species, from off central California, after someone who has done so much to educate others about the significance of the invertebrates of the coast!!

Interestingly, as I was in the process of writing it up, I suddenly became aware of multiple specimens of similar individuals from OTHER oceans in museums where I was NOT expecting to see them!

This one for example, turned out to be almost identical to the Pacific one I was working on but was from the tropical ATLANTIC! and even one from the deeps of Indonesia...

Also, unusual is how, such a moderately big animal (about 4 to 5 inches in diameter) could have gone undescribed for so long? But given how deep it was found (2100 to 4175 meters !) its been well "hidden"!

I spent many a day sorting deep-sea invertebrates on the deck of the Point Sur and I was saddened to hear about its retirement.

Bathyceramaster careyi! New genus and NEW species!

Figuring this one out required a bit of detective work, as it turns out...

Several years ago when I was working as a technician for the California Academy of Sciences, I had the pleasure of studying a newly deposited collection of deep-sea starfishes from Oregon State University.

It turned out, that one of the species in the collection was a rarely known species called "Mediaster elegans" collected by oceanographer Drew Carey. To the best of the knowledge of the workers at the time, it was thought that this was a new occurrence, since the original specimens were only known from South America (collected in 1905).

But as it turns out, after comparing Carey's specimens with the newly collected material by MBARI AND the original type series (i.e., the specimens on which the species was based) it turned out there were actually TWO species present, "Mediaster elegans" (original name) AND this one! And the one seen by Carey in 1972 was actually undescribed! So, what I'd argue was actually "Mediaster elegans" turns has not actually been seen until now...

and not only that, it had to be placed into a new GENUS in order to be correctly described!

Boom! NEW genus described! New SPECIES described!

This species was ultimately found to occur throughout the North Pacific between 1700 and 3363 meter depths!

With this one, named for Dr. Andrew Carey, formerly of Oregon State University!

The gut contents described by Carey's paper in 1972 suggests that this species feeds on deep-sea sponges.

The paper outlines several goniasterids from the North Pacific at depths below 1000 meters, including several which have not been seen since their description.

Now that the new genus Bathyceramaster has been described, I can also follow up with a note I made on one of the recent Okeanos dives to Wake Island!

This white goniasterid we saw at about 2000 m MIGHT be Bathyceramaster, but I'd need to more closely examine the surface to be sure. But if the closeups of the surface texture were correct.. I think maybe??

New discoveries that lead to new questions!!

What are they eating down there? How do they get so big? Why do some of these species always seem to be alone when you see them?

My thanks to the Monterey Bay Aquarium Research Institute, the California Academy of Sciences' Department of Invertebrate Zoology and the Museum national d'Historie naturelle in Paris!

But when it comes to "proper" nudibranchs, it turns out that they are mostly, if not entirely, carnivorous! That's right, instead of the image of "delightful little dainty, clowns of the sea" that most people seem to have of nudibranchs, perhaps we should instead think of them as hungry little monsters that chow down on all manner of other animals! Muhahah!

Note: this image probably does not accurately represent the feeding biology of dorid nudibranchs

Food and feeding in nudibranchs appears to be diverse. But like most snails, nudibranchs feed using what's called a radula, which is a belt-like structure which is modified from taxon to taxon to rasp or else assist in food or prey capture.

Some microscope images of nudibranch radula are below (images by Jeff Goddard)

Nudibranch feeding (and prey) are a HUGE topic and I'm almost certainly NOT capturing the full range. But for your SEASLUGDAY pleasure, here's some great imagery and unusual accounts of what nudibranchs eat...which really does include EVERYTHING.

5. Echinoderms (such as brittle stars)I begin with that most sinister of predatory nudibranch: the echinodermativore! To be sure, the number of sea slugs that are known to feed on echinoderms is a relatively short list-but probably one of the most gorgeous is this Indo-Pacific one: Kalinga ornata!

Here's a GREAT Japanese video of K. ornata below feeding on a brittle star (possibly Ophiocoma scolopendrina?)

3. Bryozoans & various Cnidarians (hydroids, anemones, etc.)! Among the most typical of foods fed upon by nudibranchs are the many, many types of encrusting and/or otherwise sessile animals that live on and around nudibranchs, ranging from small, colonial animals to huge tube-shaped sea anemones! Here's a nice pic, for example, of a dorid nudibranchOnchidoris muircata feeding on a bryozoan colony. Bryozoans aka "lace animals" are a phylum of colonial invertebrates that form very delicate skeletons. They are fairly common in many areas as encrusting, colonial forms.. MANY nudibranch species seem to feed on them...

Not sure which species this is..but you can see they've pretty efficiently cleared off the living tissue from the bryozoan skeleton

This species, Crimora coneja was imaged in Oregon feeding on the bryozoan colony here. You can see the stark white regions around the nudibranch where it has fed, versus the lighter, fuzzier areas around the edges.

Here's a GREAT video of Corambe steinbergae, from the west coast of North America showing this species moving across the bryzoan colony and feeding on the zooids. The nudibranch is even sort of camouflaged so that it appears hidden against the bryozoan colony..

Here's a lovely aeolid nudibranch of some kind feeding on a hydroid. One of the NEAT things about these is that many of these nudibranchs have whats called kelptocnidae which means that these slugs can actually STEAL the stinging cells from the hydroids and transfer them to their OWN body as defense!! You can read more about this here.

And there is much, much more... tunicates are also potential prey for nudibranchs!

As are sponges! In some cases, the nudibranchs can absorb the chemical defenses of the prey and utilize them for their own defense!

When we are looking at big solitary animals.. we enter the realm of animals such as the slug Tritonia and various sea anemones and sea pens... These are pretty significant predators and ellicit a fairly extreme response from they prey... The slugs in the next two videos are quite big 6 to 12 inches long.

AND as long as we are mentioning cnidarians as prey items, here's the pelagic (i.e. swimming) sea slug Glaucus atlanticus feeding on Porpita porpita (blue button jellies)

Here's a bunch of aeolids devouring a fallen Moon Jelly...

2. OTHER NUDIBRANCHSIts always interesting how many people are fascinating not just by predation but "cannibalism" which when applied to the animal world seems to mean when one "type" of animal feeds on the same or similar "type" of animal. (i.e. sea stars that feed on sea stars) and not just one species feeding on itself (as it does in humans).

Its not as common but there are several noteworthy nudibranch predators that feed on OTHER nudibranchs...

The formidible Navanax from the North Pacific for example.. They seem to be quite effiicient at swallowing their prey whole! If these were the size of say, a dog or a wolf we would be VERY afraid of them!

I've always loved the name of this nudibranch. It has a nice ring to it!

Here seen feeding on a bubble snail..

and this one, attacking and COMPLETELY SWALLOWING the sea hare, Aplysia sp.

In the tropical Indo-Pacific, there is another formidable predator, those slugs in the genus Gymnodoris, which as we'll see feed not only on other sea slugs but have progressed up to vertebrates as food!

1. SLUG EAT FISH! This really WAS the most amazing thing to discover. It turns out there's a dorid nudibranch called Gymnodoris nigricolor (name translates into the "black Gymnodoris) which attacks and EATS the FINS of certain FISH!

A hearty BONJOUR from Paris! Where Echinoblog returns to blog from a research trip at the Museum national d'Histoire naturelle!

Yes.. Echinoblog has returned to its yearly soujourn to the City of Lights! My apologies for having been remiss over the last couple of weeks. Between jet lag, research visit activities and how shall we say... "current events" things have been distractingly busy!

I am finishing up my time in Paris..but thought I would leave you with some cool collection/starfish related thoughts, especially as I've had some Star Wars on the brain lately!

A friend of mine pointed out the interesting similarity between the animals I study AND some of the details on everyone's Imperial Planet Killing space station-the Death Star!

For example, the giant offset planet-laser on the Death Star?

DOES seem to show the same kind of off-set position on a starfish! It IS one of the first things you notice about the disk when you look at it!

BUT it DID occur to me that comparing the deadly equatorial trench from the Death Star DOES present a nice analog for sharing some curious characteristic starfish parts that one does not normally think about!

Just to give one a quick frame of reference we are looking of course at TUBE FOOT GROOVES which project AWAY from the mouth

Its normal for the tube foot groove to have defense or other kinds of structures right on the edge of the "trench"

In some groups, we see more... pronounced structures that one might compare with the anti-fighter craft on the Death Star's surface..

and INDEED, there are often tiny, biting animals... crustaceans and sometimes other animals that attack the "soft parts" (i.e., the tube feet) which project from the tube foot groove.

and so yes, there is a bit of a comparison between small rebel attack fighters and annoying little, bitey crustaceans trying to take a bite out of tube feet..

Man the embattlements! Turbo lasers to the defense! Starfish don't QUITE have the anti-X-wing capabilities of the Death Star but what they DO have....

Pedicellariae!Its not QUITE clear what pedicelllariae do however. They look jaw or even clam-shaped, sometimes with numerous teeth on each piece.

SPINES!These look more analogous to "turbo lasers" in that they are extended well off the surface of the starfish's body.

Probably the most obvious part of having all these spines on the tube foot groove is the ability of those spines to CLASP shut. You would think that the Death Star engineers would have come up with something comparable.

and with that.. I'll see all of you back on the other side of the pond!